Grinding and polishing machine



Aug. 8, 1961 W. WROBBEL GRINDING AND POLISHING MACHINE 2 Sheets-Shea?I lFiled May 2o, 1958 INVENTOR /wM, /m

ATTORNEY Aug. 8, 1961 w. wRoBBEL GRINDING AND POLISHING MACHINE FiledMay 20, 1958 2 Sheets-Sheet 2 INV ENTOR AT'TORNEY United States PatentOice 2,994,990 Patented Aug. 8, 1961 2,994,999 GRINDING AND POLISHINGMACHINE Werner Wrobbel, Nurtingen, Germany, assigner to Firma MetabowerkClass, Rauch & Schmzler K.G.,

Nurtingen, Germany Filed May 20, 1958, Ser. No. 736,584 Claims priority,application Germany May 24, 19'57 4 Claims. (Cl. S1-92) This inventionrelates to a grinding and polishing machine with a stand, a supportframe vertically adjustable thereon, and a working head hingedlyysecured on the support frame and comprising a drive motor and a workingspindle operatively connected therewith, with mounting. Grinding andpolishing machines of this type have come into use in recent times forthe setting up of grinding -and polishing trains, wherein the materialto be ground and polished is conveyed on a conveyor track past aplurality of grinding and polishing machines. On these grinding andpolishing trains predominantly massproduced parts such as motor b'umperbars, decorative strips and other motor vehicle accessories are worked.If here elongated, undorned workpieces such for example as decorativestrips are worked, the grinding and polishing wheels can as a rule berigidly adjusted. When the wheel wears, the entire head of the grindingor polishing machine is shifted on the support column and clamped fastin the new position. With this type of adjustment supervision of theactual bearing pressure of the grinding or polishing wheel in relationto the workpiece sin'face is not possible. Since however the exactregulation of the bearing pressure, preferably exerted by the weight ofthe working head, is a very essential factor in the working of theworkpieces in relation to the desired nature of the workpiece surface,the adjustment of such au installation remains very time-wasting andcomplicated.

If workpieces with curved surfaces are to be machined, in the knowninstallations the working head of the grinding or polishing machines islifted hydraulically or pneumatically over copy rulers, which must bemade to imitate the workpiece surface exactly. Since the weight of thelifted head opposes the pressure of the hydraulic or pneumatic linkage,the grinding or polishing machine of this nature works rigidly in theupward direction, since the lifted weight in any case is very muchgreater than the maximumpossible bearing pressure in grinding andpolishing. If the copy ruler does not agree exactly with the workpiecesurface, or if the workpieces are not similar in form, no uniformsurface quality can be achieved. In the case of major deviations betweencopy ruler and workpiece surface, sections of the surface remain .un-`

worked, or discolorations -due to material heating occur in the case ofworkpieces of steel, which, if they are not recognised, render asatisfactory galvanic coating impossible. In such hydraulically orpneumatically controlled grinding or polishing machines the assemblybecomes more extensive and more difficult, the more the grinding orpolishing spindle is pivoted out of its horizontal position into thevertical position.

Now the invention is based upon the problem of providing a grinding andpolishing machine of the stated nature wherein with the aid of amechanical control arrangement the bearing pressure of the polishing orgrinding wheel against the surface of the workpiece can be adjustedimmediately and without trouble and regulated in nely sensitive manner,in any pivotal po'sition of the polishing or grinding spindle. Thisproblem is solved in accordance with the invention due to the fact thatthe working head, constructed as a support, is tiltable about an axislying beneath its centre of gravity and parallel to the working spindle,this axis is pivotable about an axis perpendicular to it, and thebearing pressure of the tool is regulable by a mechanical controlarrangement, lwhich is stationary in relation to the tilting movement ofthe working head, but is pivotable with the working head.

-In accordance with the invention the grinding and polishing machine canadvantageously be so' constructed that the mounting of the working headis constructed as a universal joint, and to the support frame there ishinged afork-shaped mounting piece, in which the tilting spindle of theworking head is carried. 'Ihe control arrangement can expediently beconnected in such manner with the working head that the pivot axis ofthe working head is non-rotatably connected with the mounting piecethereof, and is prolonged beyond the mounting piece towards the Workingspindle side, and a support arm forthe control arrangement is keyed onthis projection.

The control arrangement can consist according to the inventiomoftwoabutments, at least one of which is displaceable against the effect of aspring, and a control member lying between these abutments, Here eitherthe control member can be arranged o-n the working head and theabutments on the support arm or the control member can be arranged onthe support arm and the abutments on the working head.

.In a preferred form of embodiment of the object of the `invention theabutment can advantageously be so' constructed that the two abuunentsare mounted on a common guide rod and this is arranged for lengthadjustment in the support arm. The guide rod may here penetrate theabutments in a central bore in each, and the control member therebetweenin a slot. The guide rod can be adjusted in. a simple manner due to thefact that a sleeve provided with internal threading is rotatable in thesupport arm, and in it the similarly threaded end of the guide rod isscrewable but non-rotatable in relation to the support arm. 'I'headjustment can be facilitated due to the fact that the sleeve isprovided with a rotating handle. The springs of the control arrangementcan be so arranged in accordance with the invention that in each casebetween the two movable abutments and two abutments iixedly mounted onthe guide rod there is tensioned at least one helical spring, and atleast the one fixed abutment is -adjustable on the guide rod.

The control arrangement constructed in accordance with the invention canadvantageously be protected against soiling due to the fact that thehelical springs and the guide rod are surrounded withprotective tu'beswhich maybe slidable Within one another in telescopic fashion.

The control of the workpiece with the mechanical control arrangement inaccordance with the invention has the advantage that the grinding orpolishing wheel follows the shape of the workpiece surface without acopy ruler, and bears thereon with the same bearing pressureindependently of this shape, at all points of the surface. Furtheradvantages of the mechanical control consist in that it respondsimmediately, does not work with lag, can deviate upwards, Works Withoutattention, and requires no additional installation.

The invention is illustrated by way of example by reference to a formo'f embodiment of the .object thereof in the accompanying drawing,wherein:

FIGURE l-shows a grinding and polishing machine, constructed in.accordance with the invention, with horizontally set grinding or'polishing Wheel, in a lateral elevation,

FIGURE 2 shows `a front elevation thereof,

FIGURE 3 shows the lateral elevation of the same machine, withvertically working polishing or grinding wheel,

FIGURE 4 shows a plan view thereof and FIGURE 5 shows a section throughthe control arrangement, on a larger scale.

In the drawings, 1 designates a pedestal, into which a column 2.' isfitted. On this column a support frame 3 is longitudinally movablymounted. The latter is provided with a lateral projection and in thisthere is mounted a shaft 4. Upon this shaft there is mounted a supportstirrup 5 of fork-shaped construction, in which there is mounted a shaft6 perpendicularly to the shaft 4. Upon the shaft 6 a working head 7'with a drive motor 8 and a spindle mounting 9 for the working spindle 10is rockingly mounted. Upon the free end of the working spindle 10 thereis mounted a grinding or polishing tool, for example a grinding wheel11. The working head 7 can be pivoted limitedly about the spindle 6 inthe direction of the arrow 12. Furthermore by a rotation about thespindle 4 it can be brought out of the position illustrated in FIGURES land 2, with horizontally disposed spindle 10, into the positionrepresented in FIGURES 3 and 4 with vertically disposed working spindle10.

The spindle 4 is non-rotatably connected with the support stirrup 5, andis prolonged on the working spindle 10 side beyond the stirrup 5. Uponthis extension there is keyed a support arm.- 13 having a bore at itsfree end. A bushing 14 provided with internal threading is rotatably butimmovably arranged in this bore. On to the end of the bushing 14projecting upwards over the support arm 13 there is pushed a sleeve 15,which is firmly connected with the bushing 14 by a screw 16. In order tofacilitate the rotational movement the bushing 14 and the sleeve 15 canbe mounted on balls 17. A cover 18 is secured, by screws 19 for example,at the lower end of the bore of the support arm 13. In a groove .of thecover 18' there is secured an adjusting spring 20, with a screw 21,which spring extends into a groove 22 of a threaded spindle 23. In thehead end of this threaded spindle 23 there is seated a guide rod 24 uponwhich a collar 25 is mounted in vertically adjustable fashion. Betweenthe latter and a displaceable abutment member 26 there lies at least onehelical compression spring 27. The abutment member 26 rests against asupport or abutment means 28 firmly connected with the head and providedwith a slot. Through this slot there extends the guide rod 24', whichcarries above the head support 28 a further displaceable abutment member29. At least one helical compression spring 30 abuts with one endagainst abutment member 29 and with its other end on a threaded sleeve31 mounted displaceably and securably on the end of the guide rod 24.The entire control and adjusting arrangement is enclosed by tubes 32,33, 34, 35, which in part can be pushed into one another in telescopicfashion, and protect the enclosed structural parts against dirt. Thesleeve 15 is provided with a rotating handle in that a plurality ofoperating levers 36 are mounted thereon in star form.

Upon a frame 38 a sliding carriage 39 is movably arranged, carrying theworkpiece 40 to be machined. In the adjustment of the grinding andpolishing machine in accordance with the invention rstly the workingheight is coarsely set by movement of the support frame 3 on the column2. For the adjustment of the grinding or polishing wheel 11 the sleeve15 is rotated about its longitudinal axis. The threaded spindle 23thereby screws itself upwards or downwards, since it is prevented from arotational movement by the adjusting spring 20. If the threaded spindle23 moves downwards, the entire head 7 Vpivots in the direction A of thearrow 12. Due to the inclination of the head 7 and the increase ofweight involved therewith, in the pivoting direction A, the spring 27 iscompressed and opposes the increase of weight to the same extent. Inplace of one spring 27 it would be possible to provide a plurality ofsprings mounted on a movable and securable lower spring abutment andthus rendering possible an exact balance of weight, If the threadedspindle 23 is moved upwards, the spring 24 is relieved more and moreuntil the position of equilibrium of the head 7. If the latter pivotsbeyond its position of equilibrium in the direction B of the arrow 12,the spring play of the upper spring 30 or of a corresponding combinationis the same as was described previously.

Since the spindle 4 is at the same time the axis of inclination of thehead 7 and the mounting of the described control arrangement, the springplay remains the same on every adjustment of the head 7 out of thehorizontal position into the vertical position. Since however the weightof the head 1 becomes ever less and finally is completely cancelled byits pivoting into the vertical position (FIGURE 3), the threaded sleeve31 mounted on the upper end of the guide rod 24 is movably and securablyarranged. By shifting of this threaded sleeve 31 the initial tension ofthe spring can be varied within desired limits and the bearing pressureof the grinding or polishing wheel 11 against the workpiece 40 can beregulated in finely sensitive fashion. The springs 27 and 30 workingagainst one another furthermore have a vibration-damping effect upon theworking head 7.

It lies within the scope of the invention that the worlcing head 7 canalso be so mounted and securable that it can only be moved in thedirection of the arrow 12. In the case of such an arrangement the upperspring 30 or the lower spring 27 can be replaced by a xed stop. It ishere a pre-requisite that the head 7 is so secured in its direction ofmovement A or B that it does not quite reach its position ofequilibrium.

I claim: s

1. In a grinding machine or the like, in combination, support means; aworking head including a drive motor and a working spindle projectingfrom one side of said working head, said working spindle being adaptedto carry a grinding wheel and being operatively connected to said drivemotor to be driven thereby; carrying means f or carrying said workinghead on said support means and including a ilirst shaft substantiallynormal to said working spindle and turnably carried by said supportmeans, a

member xed to s-aid rst shaft for turning therewith 1 about the axisthereof, and a second substantially horizontal shaft carried by saidmember and extending substantially normal to said first shaft and beingturnably connected to said working head for carrying the latter, theaxes of said first and second shaft being located laterally from thecenter of gravity of said working head; and control means operativelyconnected to said working head and carried in part by said first shaft`for turning therewith .for resiliently balancing the turning moment ofsaid working head about the other axis and for regulating the contactpressure of the grinding wheel, said control means including iirst-abutment means comprising a pair of abutment members, second abutmentmeans sandwiched between said abutment members, and spring meansoperatively connected to said abutment members and tending to press saidabutment members against said second abutment means, one of saidabutment means being carried by said working head and the other by said4first shaft.

2. In a grinding machine or the like, in combination, support means; aworking head including a drive motor and a working spindle projectingfrom one side of said working head, said working spindle being adaptedto carry a grinding wheel and being operatively connected to said drivemotor to be driven thereby; carrying means for carrying said workinghead on said support means and insaid working spindle and turnablycarried by said support means, a:

cluding a first shaft substantially normal to member fixed to said rstshaft for turning therewith about the axis thereof, and a secondsubstantially horizontal shaft carried bysaid member and extendingsubstantially normal to said rst shaft and being turnably connected to.said working head for carrying the latter, the axes of said` lirst andsecond shaft being located laterally from theg center of gravity of saidworking head; and control means operatively connected to said workinghead and carried in part by said rst shaft for turning therewith forresiliently balancing the turning moment of said working head about theother axis and for regulating the contact pressure of the grindingwheel, said control means including rst abutment means comprising a pairof abutment members, second abutment means sandwiched between saidabutment members, and spring means operatively connected to saidabutment members and tending to press said abutment members against saidsecond abutment means, said first abutment means being carried by saidfirst shaft and said second abutment means being fixedly mounted on saidworking head.

3. In 'a grinding machine or the like, in combination, support means; aworking head including a drive motor and a working spindle projectingfrom one side of said working head, said working spindle being adaptedto carry a grinding wheel and being operatively connected to said drivemotor to be driven thereby; carrying means for carrying said workinghead on said support means and including a first shaft extendingsubstantially normal to said working spindle and turnably carried bysaid support means, a member fixed to said first shaft for turningtherewith about the axis thereof, and a second substantially horizontalshaft carried by said member extending substantially normal to saidfirst shaft and carrying said working head turnable about the axis ofsaid second shaft, the axes of said rst and second shaft being locatedlaterally from the center of gravity of said working head; a guide rodconnected to said first shaft for rotation therewith and extendingsubstantially normal thereto toward said working head; a pair ofabutment members mounted on said guide rods movable in longitudinaldirection thereof; an abutment arm projecting fixed to said working headlaterally therefrom and being sandwiched between said abutment members;and spring means operatively connected to said guide rod and abuttingagainst said abutment members and tending to press said abutment membersagainst said abutment ann.

4. In a grinding machine or the like, in combination,

support means; a working head including a drive motor and a workingspindle projecting from one side of said working head, said workingspindle being adapted to carry a grinding wheel and being operativelyconnected to said drive motor to be driven thereby; carrying means forcarrying said working head on said support means `and including a firstshaft extending substantially normal to said working spindle andturnably carried by said support means, a member fixed to said firstshaft for turning therewith about the axis thereof, Iand a secondsubstantially horizontal shaft carried by said member extendingsubstantially normal to said first shaft and carrying said working headturnable about the axis of said second shaft, the axes of said first andsecond shaft being located laterally from the center of gravity of saidworking head; a guide rod connected to said first shaft for rotationtherewith and extending substantially normal thereto toward said workinghead; a pair of abutment members mounted on said guide rods movable inlongitudinal direction thereof; an abutment arm projecting fixed to saidworking head laterally therefrom and being sandwiched between saidabutment members; means operatively connected to said guide rod formoving said guide rod in longitudinal direction; a pair of `coil springswound about said guide rod and respectively connected at one end thereofto said guide rod and engaging with the other end thereof said abutmentmembers for pressing the same respectively against said abutment arm;yand means adjustably carried by said guide rod for adjusting the springpressure of at least one of said springs.

References Cited in the file of this patent UNITED STATES PATENTS1,506,440 Norris Aug. 26, 1924 2,312,270 Simmons Feb. 23, 1943 2,353,763Rodman July 18, 1944 2,585,376 Dyer et al. Feb. 12, 1952 2,718,732Comstock Sept. 27, 1955

